There is also a concern that testosterone treatment might make prostate cancer more likely, by fuelling tumour growth.

Dr Channa Jayasena, an expert at Imperial College London and a spokesman for the UK Society for Endocrinology, said: “The message here is to select the correct patients who will benefit from testosterone therapy, but not treat it as a wonder-drug.”

The European association of Urology recommends other possible causes of low testosterone, such as obesity, should be treated before testosterone therapy is considered.